package web.servlet;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

@WebServlet("/CheckCodeServlet")
public class CheckCodeServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int width = 100;
        int height = 50;
        // 1.创建一对象,在内存中图片(验证码图片对象)
        BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // 2.美化图片
        // 2.1填充背景色
        Graphics g = img.getGraphics(); //画笔对象
        g.setColor(Color.pink); //设置画笔颜色
        g.fillRect(0, 0, width, height); //填充颜色

        // 2.2画边框
        g.setColor(Color.blue);
        g.drawRect(0, 0, width - 1, height - 1);

        // 2.3写验证码
        String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
        StringBuilder sb = new StringBuilder();//拼接验证码
        Random r = new Random();
        for (int i = 0; i < 4; i++) {
            char c = str.charAt(r.nextInt(str.length()));
            sb.append(c);
            g.drawString(c + "", 20 * (i + 1), 25);
        }

        String check_code = sb.toString();
        //存储信息到session
        request.getSession().setAttribute("check_session",check_code);

        // 2.4划线
        for (int i = 0; i < 10; i++) {
            int x1 = r.nextInt(width);
            int x2 = r.nextInt(width);
            int y1 = r.nextInt(height);
            int y2 = r.nextInt(height);
            g.setColor(Color.green);
            g.drawLine(x1, y1, x2, y2);
        }
        // 3.将图片输出到页面展示
        ImageIO.write(img, "jpg", response.getOutputStream());
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}
